Wait a sec, folks. While I don't really disagree with your posts above, and would also wonder why the surveyor suggested pulling the chainplates, there are lots of cases (and frightening pictures) of chainplates that looked fine above deck, but had corroded significantly at the part that is "inside" the deck, where moisture can get trapped and gradually corrode the chainplate. It could be that the surveyor had seen one like this recently, and was being a bit cautious, suggesting that pulling them is the only way to know if that section of the chainplate is deteriorating.
I agree with the above posts that now that you have pulled them, it is probably best to replace them with new ones, as then you won't have to worry about them for a very long time.
But I wouldn't want you thinking that the surveyor was necessarily wrong in his suggestion, or that you were wasting your time in taking them out--better safe than sorry, as losing one of these may cause the mast to fall at an inopportune time.